1. Technical Field of the Invention
The present invention relates generally to a revetment block. More particularly, the invention relates to a revetment block, used along the outer perimeter of a revetment mat, being sized to eliminate the use of half size revetment blocks, which tend to lift the edges of the revetment mat due to the flow of water thereover. Additionally, a revetment mat is disclosed adapted to use the above described revetment block along its outer perimeter and thus inhibit upward thrust on the mat from the peripheral edge.
2. Description of the Related Art
Revetment mats are used to inhibit soil erosion from areas of flowing water along, for instance, shorelines, spillways, overflow channels, drainage channels, boat ramps, and the like. Current revetment mats are formed from articulated concrete blocks that interlock together and conform to specific hydraulic performance characteristics.
U.S. Pat. No. 4,370,075, issued to Scales, FIG. 3 shows a common characteristic of revetment mats. For example, the blocks of a top row are offset and not aligned with the blocks of an immediately lower row so as to form an aligned column. This offset alignment of rows is called a xe2x80x9crunning bondxe2x80x9d and is desirable because the blocks are interlocked such that each block is in contact with a greater number of blocks for a more stable configuration. However, as a result, the edges of the revetment mat are not uniform and, as best shown in FIGS. 3 and 5, half sized blocks must be added to the ends of alternating revetment mat rows to make the row ends evenly aligned. There are several problems associated with half sized blocks. First, the half-sized blocks have contact along fewer sides or surfaces than blocks within the edges of the mat. Second, the half-size blocks have contact with fewer total blocks. These problems lead to a third problem of displacement of the half-size block. Due to their smaller size and decreased contact with adjacent blocks, the half size blocks tend to lift and rotate from an upward hydraulic thrust. Due to cable connections extending transverse to the mattress rows, the uplift of the half-size blocks can result in the curling of the edges of the revetment mat. This is highly undesirable.
In view of the deficiencies in known revetment blocks, it is apparent that a revetment block is needed for use with a revetment mat having a size which makes revetment mat rows evenly aligned, having improved hydraulic performance characteristics, and which inhibits uplift of the revetment block.
It is an object of the present invention to provide a revetment block having dimensions which, when used in a revetment mat, result in even edges of a revetment mat.
It is a further objective of this invention to provide a revetment block having a size which inhibits upward hydraulic thrust.
It is an even further objective of this invention to provide a revetment block which is used to form a revetment mat and inhibits revetment mat edge curling.
It is still an even further objective of this invention to provide a revetment block having at least one dome which slows the velocity of water passing above the revetment mat.
It is yet an even further objective to provide a revetment block having a plurality of holes therein for foliage growth.
It is also an object of the present invention to provide a revetment block having tapered sidewalls.
A revetment block, comprising a substantially rectangular block having two U-shaped vertical recesses along each of a first and a second sides, a third side having a pair of U-shaped recesses and three projections, a fourth side having three U-shaped recesses opposing the three projections of the third side and a pair of projections opposing the recesses of the third side. The revetment block has a top and a bottom surface, the top surface has a dome thereon, the dome surrounds a first and a second tapered wall opening. A third opening and a fourth opening extend from the top surface to the bottom surface of the block. The first and second tapered wall openings extend vertically downward through the dome to the bottom surface of the block. The second side has a half-dome surrounding the pair of tapered U-shaped recesses. The dome and the half-dome are formed by a curvilinear wall extending from the top surface to a flat upper plateau. The first, second, third, and fourth openings are preferably substantially rectangular. The U-shaped recesses of the first and second sides each forming one-half openings.
The revetment block further comprises at least one duct extending through said revetment block, preferably from one recess to an opposed projection. The at least one duct extends longitudinally between said third and fourth sides.
The first and second openings are vertically tapered from a wider upper portion to a narrower lower portion. The U-shaped recesses of the second side are tapered. The first, third, and fourth sides are tapered adjacent the top surface of the revetment block.
All of the above outlined objectives are to be understood as exemplary only and many more objectives of the invention may be gleaned from the disclosure herein. Therefore, no limiting interpretation of the objectives noted is to be understood without further reading of the entire specification, claims, and drawings included herewith.